Retrospective case series of suspected intentional paraquat poisonings: diagnostic findings and risk factors for death.

We investigated a cluster of canine poisonings around the 4th of July weekend in 2003 in dogs that visited a local park. Medical records review and personal interviews were performed on 17 suspect cases; 14 dogs met the case definition criteria. The 13/14 dogs were allowed off-leash at some point during their visit to the park; 7 owners noted their dog had either eaten something at the park or vomited up meat-like material within 1 h after their walk. Eleven of the 14 dogs died or were euthanized. Urine samples from 4 dogs were positive for trace amounts of paraquat and 1 vomitus sample tested positive. Tachypnea was a significant risk factor for death of the dogs. Oral or gastrointestinal ulcers were significantly correlated with recovery.